This invention relates to heat-responsive elements.
Heat-responsive elements formed from two pieces of metal attached with a layer of fusible solder have been used in fire protection devices, alarm devices, and the like to permit these devices to be operated automatically at some predetermined critical temperature. When this temperature is reached, the solder joint ruptures, thereby activating the device, e.g., to release fire suppressant material, or to sound an alarm. Pappas et al., U.S. No. 4,170,189 describes a heat-responsive element specifically for use with an alarm. Two thin link plates, at least one made of a material, e.g., stainless steel, which does not alloy significantly with solder, are joined face-to-face with a thin solder layer. The bond between the link plate and solder is weaker than the solder layer itself, and the metal/solder bond ruptures as the critical temperature is neared.